Oil and fat compositions having antifoaming effect

ABSTRACT

Oil and fat compositions containing at least 0.01% by mass of one or more polyglycerol fatty acid esters having an average degree of polymerization of 6 to 30 and an average degree of substitution of 4 to 32 have an antifoaming effect and they are usable as general-purpose oil and fat compositions having controlled foaming properties in the course of the frying, good cooking properties and a long deep-frying life.

BACKGROUND OF THE INVENTION

[0001] The present invention relates to oil and fat compositions used asgeneral-purpose cooking oils. In particular, the present inventionrelates to oil and fat compositions containing polyglycerol fatty acidesters, having a high suitability for cooking and exhibiting anexcellent antifoaming effect while they are used for cooking.

[0002] As heat-cooking oils and fats for deep-frying and stir-frying,there have been used soybean oil, rapeseed oil, corn oil, cotton seedoil, rice bran oil, safflower oil, sunflower oil, sesame oil, olive oil,coconut oil, palm oil, lard and modified oils (transesterified oils andhydrogenated oils) prepared from them alone or in the form of a mixtureof two or more of them.

[0003] In deep-frying in an oil or fat, a vapor is usually formed from amaterial being fried and, as a result, foams are formed. While thefrying is repeated, the oil or fat is deteriorated and the foamingthereof is accelerated by an influence of ingredients eluted from thematerials in the course of the deep-frying. When the foaming is serious,the materials are hidden by the foams and they cannot be seen, and thefoams overflow from the pan to make the cooking operation dangerous.Accordingly, the amount of the material that can be deep-fried in theoil is limited. Particularly when the material to be deep-fried containseggs or meats, the oil or fat is rapidly deteriorated. For controllingthe foaming of the oil in the course of the deep-frying, a silicone oilhas been added to the oil. However, the use of the silicone oil isrecently avoided because the effect thereof is limited and thebiodegradability thereof is only low.

[0004] A mixed oil of coconut oil and soybean oil and a transesterifiedoil prepared from medium length fatty acid triglycerides and rapeseedoil foam relatively easily to form a large quantity of the foams. Thefoaming of triglycerides comprising both fatty acids having 6 to 12carbon atoms and fatty acids having 14 to 22 carbon atoms cannot becontrolled even by the addition of the silicone.

DISCLOSURE OF THE INVENTION

[0005] The object of the present invention is to provide oil and fatcompositions used as general-purpose cooking oils having a longdeep-frying life, which compositions have a controlled foaming in thecourse of the frying and also good cooking properties.

[0006] After intensive investigations made for the purpose of attainingthe above-described object, the inventors have found that when aspecified polyglycerol fatty acid ester is incorporated in the oil andfat compositions, it becomes easy to remove the foam and the cookingproperties of the compositions can be improved. The present inventionhas been completed on the basis of this finding.

[0007] Namely, the present invention relates to oil and fat compositionswhich comprises triglycerides as the main components and at least 0.01%by mass of one or more polyglycerol fatty acid esters having an averagedegree of polymerization of 6 to 30 and an average degree ofsubstitution of 4 to 32. In the present invention, the higher theunsaturated fatty acid content of the fatty acids constituting thepolyglycerol fatty acid esters, the better. The oil and fat compositionswherein fatty acids constituting the triglycerides are both those having6 to 12 carbon atoms and those having 14 to 22 carbon atoms arepreferred because the effects thereof are remarkable.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] The oil and fat composition of the present invention containstriglycerides as the main components and also at least 0.01% by mass ofone or more polyglycerol fatty acid esters having an average degree ofpolymerization of 6 to 30 and an average degree of substitution of 4 to32. The term “main components” indicates that the triglyceride contentis at least 50% by mass. The oil and fat composition of the presentinvention has a triglyceride content of preferably 50 to 99.99% by mass,more preferably 50 to 99.9% by mass and particularly preferably at least90% by mass.

[0009] The glycerides mainly comprising triglycerides include oil andfat starting materials such as ordinary edible oils, transesterifiedoils, glycerol esters and hydrolyzates of them. The raw materials ofoils and fats include, for example, soybean oil, rapeseed oil, corn oil,sesame oil, sesame salad oil, perilla oil (Shiso-yu), linseed oil,peanut oil, safflower oil, safflower oil having a high oleic acidcontent, sunflower oil, sunflower oil having a high oleic acid content,cotton seed oil, grapeseed oil, macadamia nut oil, hazelnut oil, pumpkinnut oil, walnut oil, camellia oil, tea seed oil, perilla oil (Egoma-yu),borage oil, olive oil, rice bran oil, wheat germ oil, palm oil, palmkernel oil, coconut oil, cacao butter, beef tallow, lard, chicken fat,mild fat, fish oil, seal oil, alga oil, medium length fatty acidtriglycerides, these oils and fats having a saturation degree lowered bythe improvement in the quality, oils and fats obtained by thehydrogenation of them and fractionated oils and fats. The raw materialsof oils and fats are not limited to them.

[0010] The polyglycerol fatty acid esters having an average degree ofpolymerization of 6 to 30 and an average degree of substitution of 4 to32 have an effective antifoaming effect. The polyglycerol fatty acidesters can be used either alone or in the form of a mixture of two ormore of them. Although diglycerol fatty acid esters having an averagedegree of polymerization of 2 also have the antifoaming effect, theeffect is less than that of the polyglycerol fatty acid esters of thepresent invention. Polyglycerol fatty acid esters having an averagedegree of polymerization of higher than 2 and lower than 6 and anaverage degree of polymerization of lower than 4 have no antifoamingeffect and, they sometimes have a contrary effect. They have a lowsolubility in fats and oils and the obtained solution is cloudy or aninsoluble matter deposits or precipitates therein in many cases. On thecontrary, the polyglycerol fatty acid esters having an average degree ofpolymerization of 6 to 30 and an average degree of substitution of 4 to32 have an effective antifoaming effect, and a high solubility in oilsand fats. Those having an average degree of polymerization of 9 to 25and an average degree of substitution of 5 to 27 are preferred, andthose having an average degree of polymerization of 11 to 20 and anaverage degree of substitution of 6 to 20 are more preferred.

[0011] The average degree of substitution is not higher than “averagedegree of polymerization +2”. For example, when the average degree ofpolymerization is 10, the average degree of substitution is not higherthan 12.

[0012] In the present invention, the term “average degree ofpolymerization of polyglycerol fatty acid esters” indicates the averagedegree of polymerization of the polyglycerols constituting the esters.The average degree of polymerization (n) of the polyglycerols isdetermined from the measured hydroxyl group value (OHV) of thepolyglycerols and the theoretical value according to formula (3) givenbelow. The hydroxyl group value (OHV) of the polyglycerols is determinedby the standard oil-and-fat analysis method. The average molecularweight (MW) is determined by the following formula (1):

MW=74n+18  (formula 1)

OHV=56110(n+2)/MW  (formula 2)

[0013] From formulae (1) and (2):

n=(112220−18×OHV)/(74×OHV−56110)  (formula 3)

[0014] In the present invention, the average degree of substitution isdetermined from the molar ratio of polyglycerols to fatty acidssubjected to the reaction for synthesizing the polyglycerol fatty acidesters. The molar ratio of compounds subjected to the reaction is theratio of the amount (mole) of the polyglycerols subjected to thereaction to the amount (mole) of the fatty acids subjected to thereaction, wherein the amount (mole) of the polyglycerols subjected tothe reaction is determined by dividing the mass (grams) of thepolyglycerols subjected to the reaction by the average molecular weight(MW) of the polyglycerols determined from the above-described,determined hydroxyl group value of the polyglycerols. For example, thepolyglycerol fatty acid esters of the present invention having anaverage degree polymerization of 15 and an average degree ofsubstitution of 8 have a measured hydroxyl group value of the chargedpolyglycerols of 846, and the average degree of polymerization (n) ofpolyglycerols is 15 and the average molecular weight (MW) of 1128according to the above-described formulae. After the synthesis by using1128 g (1 mol) of the polyglycerols and oleic acid (8 mols), the averagedegree of polymerization and the average degree of substitution aredetermined to be 15 and 8, respectively. In this case, thesaponification value and hydroxyl group value of the polyglycerol fattyacid esters are determined to be 130 to 160 and 130 to 160,respectively.

[0015] When the unsaturated fatty acid content of the total constituentfatty acids in the polyglycerol fatty acid esters is less than 50% bymass, the solubility of the esters in the oils and fats is often not ashigh as expected. In some cases, the obtained solution is cloudy or aninsoluble matter deposits or precipitates therein. Therefore,unsaturated fatty acid content of the total constituent fatty acids inthe polyglycerol fatty acid esters is preferably 50 to 100% by mass andmore preferably 70 to 100% by mass.

[0016] In the present invention, the term “constituent fatty acidcontent” is a numerical value obtained by methyl-esterifying ortrimethyl-silylating the polyglycerol fatty acid esters and calculatingit from the fatty acid composition analyzed by GLC (gas chromatography).

[0017] Generally, oils and fats containing medium length fatty acids,such as mixed oils of medium length fatty acid triglycerides and longchain fatty acid triglycerides, or transesterified oils of them,violently make foams. In such a case, the oil and fat composition of thepresent invention exhibits a remarkable effect and is suitably used.Namely, the constituent fatty acids of the triglycerides preferablycontain medium length fatty acids (6 to 12 carbon atoms). In particular,when the constituent fatty acids of the triglycerides in the oil and fatcomposition include both fatty acids having 6 to 12 carbon atoms andfatty acids having 14 to 22 carbon atoms, the antifoaming effect of thepresent invention is remarkable. Thus, those fatty acids are preferred.In such a case, the remarkable effect can be obtained particularly whenthe ratio (% by mass) of the fatty acids having 6 to 12 carbon atoms tothe fatty acids having 14 to 22 carbon atoms is 5:95 to 95:5.

[0018] The polyglycerol fatty acid esters used in the present inventionare generally obtained by the transesterification reaction of apolyglycerol, obtained by the dehydration condensation of glycerol orsynthesized from glycidol or epichlorohydrin, with a fatty acid.However, the method for synthesizing those polyglycerol fatty acidesters is not limited to this method.

[0019] The aliphatic carboxylic acids constituting the polyglycerolfatty acid esters are preferably saturated linear fatty acids,unsaturated linear fatty acids and organic acids each having 2 to 22carbon atoms. Examples of them include caproic acid, caprylic acid,capric acid, lauric acid, myristic acid, palmitic acid, stearic acid,arachidic acid, behenic acid, lignoceric acid, cerotic acid,palmitooleic acid, oleic acid, elaidic acid, linoleic acid, linolenicacid, eicosapentaenoic acid, docosahexaenoic acid, arachidonic acid,erucic acid, hydroxyfatty acids, ricinoleic acid, condensed ricinoleicacid, acetic acid and isobutyric acid. However, the aliphatic carboxylicacids are not limited to them. In these acids, fatty acids having 8 to20 carbon atoms are preferred and those having 12 to 18 carbon atoms aremore preferred.

[0020] The oil and fat composition of the present invention contains atleast 0.01% by mass, preferably 0.01 to 10% by mass and more preferably0.1 to 5% by mass, of the polyglycerol fatty acid esters. The oil andfat composition containing 0.1 to 3% by mass of the polyglycerol fattyacid esters has the best cooking properties.

[0021] The oil and fat composition of the present invention obtained asdescribed above is usable for the cooking as it is or after theincorporation of additives usually added to cooking oil and fatcompositions.

[0022] The additives are those used for the purposes of obtaining thesynergistic antifoaming effect, improving the storability, improving theoxidation stability, improving heat stability and inhibiting thecrystallization at a low temperature, such as polyglycerol fatty acidesters, sucrose fatty acid esters, glycerol fatty acid esters, sorbitanfatty acid esters, sorbitol fatty acid esters, vitamin E, ascorbic acidfatty acid esters, lignan, coenzyme Q, phospholipids, silicone oil andoryzanol; and also those used for the purposes of preventing adultdiseases, preventing diseases caused by life habits, controlling in vivooxidation and preventing adiposis, such as vitamin E, ascorbic acidfatty acid esters, lignan, coenzyme Q, phospholipids and oryzanol.

[0023] The cooking oil and fat composition of the present invention hasa flavor and a taste equivalent or superior to those of ordinaryvegetable oils available on the market, such as rapeseed oil, corn oil,safflower oil and soybean oil. This composition is usable not only formaking stir-fried foods, deep-fried foods, marinades, etc. but also formaking foods containing an oil or a fat, such as dressings, mayonnaise,margarine, confectioneries, cakes and drinks.

[0024] The following Examples will further illustrate the presentinvention, which by no means limit the invention.

EXAMPLES

[0025] <Preparation of Polyglycerol Fatty Acid Esters>

[0026] Glycerol was mixed with sodium hydroxide. The obtained mixturewas heated to 90° C. and then dried under reduced pressure. The mixturewas then heated at 200 to 270° C. and stirred to conduct the reaction.After the completion of the reaction, the reaction mixture was filteredto obtain polyglycerols. The polyglycerols were various depending on thereaction temperature in the above-described range. Diglycerol (averagedegree of polymerization: 2) was obtained by the molecular distillationof the synthesized polyglycerols. Polyglycerols having an average degreeof polymerization of higher than 10 were obtained by GPC ofpolyglycerols having an average degree of polymerization of 10 to removethose having a low degree of polymerization. Various polyglycerolsobtained as described above were mixed with various fatty acids toconduct the reaction in the presence of sodium hydroxide as the catalystat 200° C. in nitrogen gas stream to obtain polyglycerol fatty acidesters (a to w). The polyglycerol fatty acid esters thus obtained areshown in Table 1 given below.

[0027] The average degree of polymerization and the average degree ofsubstitution were determined according to the above-describedcalculation formulae. TABLE 1 Polyglycerol fatty acid esters Averagedegree Average degree Main fatty acids (%) of polymerization ofsubstitution C_(12:0) C_(14:0) C_(16:0) C_(18:0) C_(18:1) C_(18:2) a 2 130 15 45 10 b 4 1 9 6 80 5 c 4 4 31 69 d 5 6 9 6 80 5 e 6 5 9 6 80 5 f 88 28 25 41 6 g 9 6 9 6 80 5 h 10 1 9 6 80 5 i 10 10 9 6 80 5 j 15 8 7 274 17 x 15 7 3 5 45 1 40 7 w 10 9 34 3 2 4 51 6

Comparative Examples 1 to 12 and Examples 1 to 10

[0028] Comparative fat and oil compositions and the fat and oilcompositions of the present invention shown in Tables 2 and 3 wereprepared and they were subjected to a foam-height test and a solubilitytest.

[0029] (Foam Height Tests)

[0030] 20 g of each of oil and fat compositions was fed into a test tube(diameter: 25 mm, length: 200 mm) and heated to 160° C. with a blockheater (Dry Thermo Unit DTU-20 TAITEC CORPORATION). A potato cube havinga size of 1 cm×1 cm×1 cm was thrown into the composition, and thehighest height, from the oil surface level measured before the heating,of generated foams was taken as the foam height.

[0031] Evaluation:

[0032] ≦40 mm : Antifoaming effect was recognized.

[0033] 40<≦80 mm : Slight antifoaming effect was recognized.

[0034] >80 mm : Antifoaming effect was not recognized.

[0035] (Determination of Solubility)

[0036] 100 g of each of the oil and fat compositions was fed into a 200ml beaker, heated to 50° C. and cooled to 30° C. Whether a clouding,milky opaqueness or the formation of insoluble matter was found or notwas examined.

[0037] Evaluation:

[0038] ◯: Clear

[0039] Δ: Slight milky opaqueness or insoluble matter was found.

[0040] X: Milky opaqueness or the formation of insoluble matter wasfound. TABLE 2 Composition and evaluation (parts by mass) ComparativeExample Example 1 2 3 4 5 6 1 2 3 4 5 (Oil and fat composition)(Deteriorated) rapeseed oil 100 99 99 99 99 99 99 99 99 99 99(shirasame-yu) a 1 b 1 c 1 d 1 e 1 f 1 g 1 h 1 i 1 j 1 Height of foams(mm) 113 45 110 100 86 90 37 30 25 18 15 Solubility ◯ Δ ◯ X ◯ X ◯ Δ ◯ ◯◯

[0041] TABLE 3 Composition and evaluation (parts by mass) ComparativeExample Example 7 8 9 10 11 12 6 7 8 9 10 (Oil and fat composition)(Deteriorated) sesame 100 95 99 94 99 94 salad oil (Deteriorated) MCT 55 5 (Deteriorated) MLCT 100 99 99 99 99 b 1 d 1 e 1 f 1 g 1 h 1 i 1 j 1Height of foams (mm) 115 130 127 114 120 95 36 37 29 25 17 Solubility ◯◯ ◯ ◯ ◯ X ◯ Δ ◯ ◯ ◯

Comparative Examples 13 to 15 and Examples 11 to 17

[0042] Comparative oil and fat compositions and the oil and fatcompositions of the present invention shown in Table 4 were prepared andsubjected to a deep-frying test.

[0043] (Deep-Frying Test)

[0044] 600 g of each of oil and fat compositions was fed into anelectric home cooking fryer, and 6 deep-fried shrimps, 4 pieces ofcroquettes, 10 pieces of deep-fried chicken and 10 pieces of breadedpork cutlets were prepared therein at 180° C. The degree of foaming ofthe oil, emitting of smoke after the completion of the test and thetaste of the fried foods were evaluated.

[0045] (Determination of Foaming):

[0046] ⊚: excellent

[0047] ◯: ordinary foaming

[0048] Δ: strong foaming

[0049] X: violent foaming

[0050] (Evaluation of Taste)

[0051] As compared with rapeseed oil (shirashime-yu):

[0052] ⊚: equivalent

[0053] Δ: The flavor and taste are a little different, but thedifference is insignificant.

[0054] X: The flavor and taste are different and the deep-fried food didnot taste good. TABLE 4 Composition and evaluation (parts by mass)Comparative Example Example 13 14 15 11 12 13 14 15 16 17 (Oil and fatcomposition) Rapeseed oil (shirasame-yu) 85 97 98 Sesame salad oil 10095 82 99 92 MCT 5 5 5 MLCT 100 99.5 e 15 3 g 13 2 3 j 1 0.5 (Foaming)Deep-fried shrimps ◯ X ◯ ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ Croquettes ◯ X Δ ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ ⊚Deep-fried chicken Δ X Δ ⊚ ⊚ ◯ ⊚ ⊚ ⊚ ⊚ Breaded pork cutlets X X X ⊚ ⊚ ◯⊚ ◯ ◯ ⊚ Smoking ◯ Δ ◯ X Δ ◯ ◯ ◯ ◯ ◯ Flavor and taste ◯ ◯ ◯ X Δ ◯ ◯ ◯ ◯ ◯

Examples 18 and 19

[0055] Deep-frying tests were conducted by using MLCT containing 2% bymass (g) or 0.5% by mass (x) of polyglycerol fatty acid esters (Example18) or 2% by mass (g) or 0.5% by mass (w) of polyglycerol fatty acidesters (Example 19). In both Examples 18 and 19, the cooking waspossible without any problem, and the cooked foods had excellent flavorand taste. After keeping the oils at 0° C. for 2 weeks, both oils usedin Examples 18 and 19 were transparent and clear, and no milkyopaqueness or the formation of insoluble matter was found.

[0056] As described above in detail, the present invention relates tooil and fat compositions used as general-purpose cooking oils having along deep-frying life, which compositions have a controlled foaming inthe course of the frying and also good cooking properties.

What is claimed is:
 1. Oil and fat compositions exhibiting anantifoaming effect, which comprises triglycerides as the main componentsand at least 0.01% by mass of one or more polyglycerol fatty acid estershaving an average degree of polymerization of 6 to 30 and an averagedegree of substitution of 4 to
 32. 2. The oil and fat compositionsaccording to claim 1 wherein the polyglycerol fatty acid ester contentis 0.01 to 10% by mass.
 3. The oil and fat compositions according toclaim 1 wherein the average degree of polymerization of the polyglycerolfatty acid esters is 9 to 25 and the average degree of substitutionthereof is 5 to
 27. 4. The oil and fat compositions according to claim 1wherein the average degree of polymerization of the polyglycerol fattyacid ester is 11 to 20 and the average degree of substitution thereof is6 to
 20. 5. The oil and fat compositions according to claim 1 whereinthe unsaturated fatty acid content of the fatty acids constituting thepolyglycerol fatty acid esters is 50 to 100% by mass based on the totalconstituting fatty acids.
 6. The oil and fat compositions according toclaim. 1 wherein the fatty acids constituting the triglycerides includethose having 6 to 12 carbon atoms.
 7. The oil and fat compositionsaccording to claim 1 wherein the fatty acids constituting thetriglycerides include those having 6 to 12 carbon atoms and those having14 to 22 fatty acids.
 8. The oil and fat compositions according to claim7 wherein the constituting ratio (% by mass) of the fatty acids having 6to 12 carbon atoms to those having 14 to 22 carbon atoms is 5:95 to95:5.
 9. The oil and fat compositions according to claim 1 wherein thealiphatic carboxylic acids constituting the polyglycerol fatty acidesters have 2 to 22 carbon atoms.
 10. The oil and fat compositionsaccording to claim 1 which contain 50 to 99.99% by mass of thetriglycerides.
 11. Oil and fat compositions exhibiting an antifoamingeffect, which comprises 50 to 99.99% by mass of triglycerides and 0.01to 10% by mass of one or more polyglycerol fatty acid esters having anaverage degree of polymerization of 6 to 30 and an average degree ofsubstitution of 4 to 32 wherein fatty acids constituting thetriglycerides include those having 6 to 12 carbon atoms and those having14 to 22 fatty acids and wherein unsaturated fatty acid content of thefatty acids constituting the polyglycerol fatty acid esters is 50 to100% by mass based on the total constituting fatty acids.
 12. The oiland fat compositions according to claim 11 wherein the average degree ofpolymerization of the polyglycerol fatty acid esters is 9 to 25 and theaverage degree of substitution thereof is 5 to
 27. 13. The oil and fatcompositions according to claim 11 wherein the average degree ofpolymerization of the polyglycerol fatty acid ester is 11 to 20 and theaverage degree of substitution thereof is 6 to
 20. 14. The oil and fatcompositions according to claim 11 wherein the constituting ratio (% bymass) of the fatty acids having 6 to 12 carbon atoms to those having 14to 22 carbon atoms is 5:95 to 95:5.
 15. The oil and fat compositionsaccording to claim 11 wherein the aliphatic carboxylic acidsconstituting the polyglycerol fatty acid esters have 2 to 22 carbonatoms.
 16. A method of using the oil and fat compositions according toclaim 1 as edible oils and fats.
 17. A method of using the oil and fatcompositions according to claim 11 as edible oils and fats.
 18. A methodof cooking foods which comprises the step of using the oil and fatcompositions of claim 1 in cooking of foods.
 19. A method of cookingfoods which comprises the step of using the oil and fat compositions ofclaim 11 in cooking of foods.